Outcomes of Extra-articular, Intra-epiphyseal Drilling for Osteochondritis Dissecans of the Knee

Background: When conservative management fails to heal femoral condyle osteochondritis dissecans (OCD) lesions in a child, then drilling of the subchondral plate below the lesion to stimulate healing may be beneficial. This study reviews the outcomes of extra-articular, intraepiphyseal drilling of OCD lesions of the knee with intact articular cartilage. Methods: Over an 8-year period, all children, who failed at least 6 months of nonoperative management, underwent arthroscopic knee surgery and extra-articular, intra-epiphyseal drilling for their symptomatic, nondisplaced femoral condyle OCD lesions. The clinical and radiographic outcomes were evaluated by using demographics, preoperative size of the lesion, intraoperative concomitant pathology, complications, postoperative range of motion, return to activities, radiographic progression of healing, and subsequent operative procedures. Results: In all 59 children, the mean time to return to activities was 2.8 months (1.3 to 13.1mo) and the mean percentage of radiographic healing was 98.2% (79% to 100%) at final follow-up. Forty-four (75%) of the OCD lesions were successfully treated to 100% radiographic healing with an average time for healing of 11.9 months (1.3 to 47.3 mo). The large lesions took significantly longer to heal than the small lesions, 15.3 months versus 8.8 months (P=0.032), and the percentage of radiographic healing at final follow-up approached significance with large (> 3.2cm(2)) lesions attaining a mean of 96.9% (standard deviation 6.4%) versus small lesions (< 3.2cm(2)) with a mean of 99.4%(standard deviation 2.1%, P=0.083). No operative complications were observed. Conclusions: Extra-articular, intraepiphyseal drilling of OCD lesions produced excellent results over the historical controls using intra-articular drilling for those patients who failed initial conservative management. This technique allows for more drill holes to be placed perpendicular to the OCD lesions, especially the posterior lesions that may have limited intra-articular access. Furthermore, this technique avoids intraoperative damage to the overlying intact articular cartilage and promotes osseous healing by fenestration of the sclerotic rim surrounding the OCD lesion. Level of Incidence: Prognostic study, Level IV (retrospective study).